The state Department of Environmental Quality is investigating reports that passengers aboard a ferry crossing the Mississippi River just below New Orleans complained of eye and throat irritation, according to State Police and the St. Bernard Parish Sheriff's Office.

According to a report on WVUE-TV,
a DEQ spokesman said air quality tests showed the presence of sulphur
dioxide, a potentially hazardous chemical. Officials suspect the
possible release came from the Rain CII plant in Chalmette.

The Sheriff's Office said it was called about 6 p.m. by someone on the ferry, who reported the passengers' complaints and said there was a gray cloud sitting above the river. The ferry had been crossing the river from Algiers to Chalmette.

A nearby chemical plant had been shut down for the past week but began producing again Friday, according to a State Police spokeswoman, Trooper Melissa Matey.

Calls to officials with DEQ and Rain CII plant were not immediately returned.

The Rain CII plant produces calcined petroleum coke by heating petroleum coke produced by oil refineries to remove contaminants so the carbon-based material can be turned into anodes for production of aluminum.

That process removes sulphur dioxide from the coke.

According to DEQ records, Rain CII was verbally granted a variance on Nov. 30 to increase the number of hours that a piece of equipment called a pyroscrubber stack was allowed to vent sulphur dioxide and other pollutants into the air at the company's Chalmette Coke Plant. According to an approval letter signed Dec. 5 by DEQ Assistant Secretary Sam Phillips confirming the earlier variance approval, the variance was required because of "another boiler tube rupture which has disabled the waste heat recovery system" that normally removed the pollutants.

However, the variance does not allow an increase in the allowed amount of sulphur dioxide that already was being emitted from the plant, which would have been 268.8 tons through Feb. 28, the end of the variance period, according to the letter.

Normally, the gas stream is vented through the plant's waste heat boiler or baghouse, both of which are pollution reduction processes. But the company also is allowed to use the Pyroscrubber Stack as a bypass for up to 500 hours a year during outages of the waste heat boiler or baghouse.

The variance would add to the bypass total by 336 hours, according to the DEQ variance.

"A variance does not authorize the maintenance of a nuisance or a danger to public health and safety," said the letter from Phillips.